x = 0:0.01:10;
y1 = cos(0.4*pi*x);
y2 = cos((8/5)*pi*x);

plot(x, y1, '-b', 'LineWidth', 2)
hold on;
plot(x, y2, '-r', 'LineWidth', 2)

set(gca, 'Box', 'off', 'FontSize', 20, ...
         'XLim', [0, 10], 'YLim', [-1.05, 1.05], ...
         'XTick', 0:2:10, 'YTick', -1:0.5:1, ...
         'TickDir', 'out')
xlabel('Time', 'FontSize', 20)

set(gcf, 'Position', [200, 100, 1000, 600])